[CRIU] [PATCH 2/2] p.haul: use ssh tunneling and controll it with ssh* cmdline opts

[Ruslan Kuprieiev]

On 27.10.2014 20:39, Pavel Emelyanov wrote:
> 		_rpc_proxy_caller(self._rpc_sk, RPC_CMD, "init_rpc")(args)
>>>> @@ -51,7 +57,17 @@ class rpc_proxy:
>>>>    
>>>>    	def _make_sk(self):
>>>>    		sk = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
>>>> -		sk.connect((self._srv, rpc_port))
>>>> +		# ssh tunnel needs some time to start working, so lets
>>>> +		# make CONNECT_ATTEMPTS attempts to connect.
>>> I don't like it. Can you shed more light on what's going on here?
>> We have no way to check if ssh tunnel is created other than try to connect.
> Yes, and AFAIU when you connect to local ssh, it "blocks" the
> connection and goes to connect remotely. I don't see the need
> in retries.

There is a race condition happening, ssh can't bind to local port so fast.
So we need to try to connect a bunch of times(not using connection timeout)
and only then fail.

>> But I should have used connection timeout here =). Will fix.
>>
>>>> +		for n in xrange(CONNECT_ATTEMPTS):
>>>> +			try:
>>>> +				sk.connect(self._srv)
>>>> +			except socket.error as e:
>>>> +				if e.errno != errno.ECONNREFUSED or n == CONNECT_ATTEMPTS - 1:
>>>> +					raise e
>>>> +				else:
>>>> +					continue
>>>> +			break
>>>>    		host = _rpc_proxy_caller(sk, RPC_CMD, "get_name")()
>>>>    		return (sk, host)
>>>>